package util;

import java.io.UnsupportedEncodingException;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import sun.misc.BASE64Encoder;  
import sun.misc.BASE64Decoder;  

@SuppressWarnings("restriction")
public class EncryptFunc {
	private final static String DES = "DES";
    private final static String ENCODE = "UTF-8";
    
    /**
     * DES 加密，key必须是8的倍数位
     */
	private static String DEFAULt_DES_KEY = "!@#$%^&*";
	
	public static String desEncrypt(String data,String key) throws UnsupportedEncodingException, Exception{
		if(StringUtils.isEmpty(key)){
			key = DEFAULt_DES_KEY;
		}
		
		byte[] bt = encrypt(data.getBytes(ENCODE), key.getBytes(ENCODE));
        String strs = new BASE64Encoder().encode(bt);
        return strs;
	}
	
	public static String desDecrypt(String data,String key) throws Exception{
		if(StringUtils.isEmpty(key)){
			key = DEFAULt_DES_KEY;
		}
		BASE64Decoder decoder = new BASE64Decoder();
        byte[] buf = decoder.decodeBuffer(data);
        byte[] bt = decrypt(buf, key.getBytes(ENCODE));
        return new String(bt, ENCODE);
	}
	
	
	public static void main(String[] args) {
		String data = "test";
		try {
			String encrypt = desEncrypt(data, null);
			System.out.println(encrypt);
			
			String decrypt = desDecrypt(data, null);
			System.out.println(decrypt);
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	
	
	/**
     * Description 根据键值进行加密
     * 
     * @param data
     * @param key
     *            加密键byte数组
     * @return
     * @throws Exception
     */
    private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源
        SecureRandom sr = new SecureRandom();

        // 从原始密钥数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);

        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);

        // Cipher对象实际完成加密操作
        Cipher cipher = Cipher.getInstance(DES);

        // 用密钥初始化Cipher对象
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);

        return cipher.doFinal(data);
    }
    
    /**
     * Description 根据键值进行解密
     * 
     * @param data
     * @param key
     *            加密键byte数组
     * @return
     * @throws Exception
     */
    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源
        SecureRandom sr = new SecureRandom();

        // 从原始密钥数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);

        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);

        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance(DES);

        // 用密钥初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);

        return cipher.doFinal(data);
    }
}
